Commit 89a3dfb7 authored by Maxime Ripard's avatar Maxime Ripard Committed by Michael Turquette

clk: sunxi-ng: Add fractional lib

Some clocks can be switched to a mode called fractional that have two fixed
output rate you can choose from.

Add a small library to deal with those clocks.
Signed-off-by: default avatarMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: default avatarMichael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20160629190535.11855-4-maxime.ripard@free-electrons.com
parent 1d80c142
config SUNXI_CCU
bool "Clock support for Allwinner SoCs"
default ARCH_SUNXI
if SUNXI_CCU
# Base clock types
config SUNXI_CCU_FRAC
bool
endif
# Common objects
obj-$(CONFIG_SUNXI_CCU) += ccu_common.o
obj-$(CONFIG_SUNXI_CCU) += ccu_reset.o
# Base clock types
obj-$(CONFIG_SUNXI_CCU_FRAC) += ccu_frac.o
/*
* Copyright (C) 2016 Maxime Ripard
* Maxime Ripard <maxime.ripard@free-electrons.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*/
#include <linux/clk-provider.h>
#include <linux/spinlock.h>
#include "ccu_frac.h"
bool ccu_frac_helper_is_enabled(struct ccu_common *common,
struct _ccu_frac *cf)
{
if (!(common->features & CCU_FEATURE_FRACTIONAL))
return false;
return !(readl(common->base + common->reg) & cf->enable);
}
void ccu_frac_helper_enable(struct ccu_common *common,
struct _ccu_frac *cf)
{
unsigned long flags;
u32 reg;
if (!(common->features & CCU_FEATURE_FRACTIONAL))
return;
spin_lock_irqsave(common->lock, flags);
reg = readl(common->base + common->reg);
writel(reg & ~cf->enable, common->base + common->reg);
spin_unlock_irqrestore(common->lock, flags);
}
void ccu_frac_helper_disable(struct ccu_common *common,
struct _ccu_frac *cf)
{
unsigned long flags;
u32 reg;
if (!(common->features & CCU_FEATURE_FRACTIONAL))
return;
spin_lock_irqsave(common->lock, flags);
reg = readl(common->base + common->reg);
writel(reg | cf->enable, common->base + common->reg);
spin_unlock_irqrestore(common->lock, flags);
}
bool ccu_frac_helper_has_rate(struct ccu_common *common,
struct _ccu_frac *cf,
unsigned long rate)
{
if (!(common->features & CCU_FEATURE_FRACTIONAL))
return false;
return (cf->rates[0] == rate) || (cf->rates[1] == rate);
}
unsigned long ccu_frac_helper_read_rate(struct ccu_common *common,
struct _ccu_frac *cf)
{
u32 reg;
printk("%s: Read fractional\n", clk_hw_get_name(&common->hw));
if (!(common->features & CCU_FEATURE_FRACTIONAL))
return 0;
printk("%s: clock is fractional (rates %lu and %lu)\n",
clk_hw_get_name(&common->hw), cf->rates[0], cf->rates[1]);
reg = readl(common->base + common->reg);
printk("%s: clock reg is 0x%x (select is 0x%x)\n",
clk_hw_get_name(&common->hw), reg, cf->select);
return (reg & cf->select) ? cf->rates[1] : cf->rates[0];
}
int ccu_frac_helper_set_rate(struct ccu_common *common,
struct _ccu_frac *cf,
unsigned long rate)
{
unsigned long flags;
u32 reg, sel;
if (!(common->features & CCU_FEATURE_FRACTIONAL))
return -EINVAL;
if (cf->rates[0] == rate)
sel = 0;
else if (cf->rates[1] == rate)
sel = cf->select;
else
return -EINVAL;
spin_lock_irqsave(common->lock, flags);
reg = readl(common->base + common->reg);
reg &= ~cf->select;
writel(reg | sel, common->base + common->reg);
spin_unlock_irqrestore(common->lock, flags);
return 0;
}
/*
* Copyright (c) 2016 Maxime Ripard. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _CCU_FRAC_H_
#define _CCU_FRAC_H_
#include <linux/clk-provider.h>
#include "ccu_common.h"
struct _ccu_frac {
u32 enable;
u32 select;
unsigned long rates[2];
};
#define _SUNXI_CCU_FRAC(_enable, _select, _rate1, _rate2) \
{ \
.enable = _enable, \
.select = _select, \
.rates = { _rate1, _rate2 }, \
}
bool ccu_frac_helper_is_enabled(struct ccu_common *common,
struct _ccu_frac *cf);
void ccu_frac_helper_enable(struct ccu_common *common,
struct _ccu_frac *cf);
void ccu_frac_helper_disable(struct ccu_common *common,
struct _ccu_frac *cf);
bool ccu_frac_helper_has_rate(struct ccu_common *common,
struct _ccu_frac *cf,
unsigned long rate);
unsigned long ccu_frac_helper_read_rate(struct ccu_common *common,
struct _ccu_frac *cf);
int ccu_frac_helper_set_rate(struct ccu_common *common,
struct _ccu_frac *cf,
unsigned long rate);
#endif /* _CCU_FRAC_H_ */
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